You really do want an aluminum radiator, huh? I think someone here said they're only useful for racing. Would be overkill for a street car.

As far as cleaning vs. re-coring, I believe a shop would need the radiator out of the car for this also. I think they even need the radiator out to pressure test it. From what I recall (it's been a while) a rad. shop will disassemble the radiator, taking the top, bottom and sides off. Then they'd dip the core in some caustic crap. A little pokey pokey with some long rods. Then they'd re-braze all the pieces back together and shoot it with black spray paint. I've always had good luck going to areas like Wilmington where there are many radiator shops. Competition keeps the prices in check. You might look around for a similarly automotive industrial area around you. Look for lots of junk yards, tire shops and radiator shops.

I seriously would take the radiator out myself. You will be much more careful in removing it than a shop would. It shouldn't be too much work and you can take the opportunity to clean up any leaves and dirt around in that area.